Display screen or portion thereof having a graphical user interface for a process control editor



The FIGURE is a front view of a display screen or portion thereof having a graphical user interface for a process control editor showing our new design.

The outermost broken lines illustrate an electronic device, the broken line at the periphery of the graphical user interface illustrates the display screen or portion thereof, and the remaining broken line showing of text, numbers and graphical images illustrate portions of the graphical user interface. None of the broken lines form part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof having a graphical user interface for a process control editor, as shown and described. 